[Buckeye McFrog]

I rented a house once that had well water and city sewer. They metered my well so they knew what to charge me for the sewage. Weird.

[William Tell]

Buckeye McFrog said: "They metered my well so they knew what to charge me for the sewage. "

I think this is fairly typical. I used to own a condo where they did the same thing and then made seasonal adjustments to account for landscape irrigation.